Hhmmm... interesting question. Have u tried it with different types of wood? Because some of the softer woods mite readily split. And I suppose it depends on how much force the knife impacts with.

Most anime style images use exaggeration to emphasise ability. The master plants the knife in with such force that it buries almost to the hilt, which is sure to crack the wood. So i guess it depends what u want too show, a knife thats been 'placed' in the the table, or a knife thats been rammed into the table. I'd go for the later Especially for the anime effect